Method of polymerization using a grignard reagent/ketone catalyst complex to producecrystalline methacrylate polymers



United States Patent s 151 102 MnTn'on on PoLizMEmzATIoN USING A GRIGNARD REAGENT/KETONE CATALYST COMPLEX T0 PRODUCE CRYSTALLINE 3,151,102 Patented Sept. 29, 1964 and hydrogen, and R" is a hydrocarbon radical of 1 to 18 carbon atoms.

The following specific examples illustrate the process of this invention and the manner of carrying out the METHACRYLATE PGLYMERS polymerization. All parts and percentages are by weight Abraham Kutner, Newark, Del., assignor to Hercules unless otherwise indicated, and parts and moles are in Powder Company, Wilmington, Del., a corporation of h Same unite Delaware EXAMPLES No Drawing. Filed Dec. 5, 1958, Ser. No. 778,286

9 Claims (CL 260-895) An ether solution of Grignard reagent was prepared by This invention relates to an improved method for makreacting a hydrocarbon halide in a nitrogen atmosphere i ni bl Polymers f which Crystalline 1 wlth an equimolecular amount of magnesium turnings in (methyl methacrylate) and crystalline poly(methyl haloether to which a trace of iodine was added. The ether acrylate) are readily isolat d, solution was allowed to settle so as to get a clear solution, P l hibi i the Phenomena f crystallization and this was analyzed and used in the form of an ether are known in the art. Such polymers are fusible, mold- 501311031 for the reaction with ketoheable, and extrudable, and when melted and rapidly cooled A measured amount of this Grighal'd Teagfint and a are i i i ll amorphous b may he erystanized by vari measured amount of the indicated ketone were mixed toous known techniques. The crystalline polymers have gethel' the Catalysi- The action forming the higher service temperatures and greater strength but catalyst is rapid and was Completed y heating at lower flexibility and transparency than the corresponding Methyl me'fhacfylflte methyl haloacfylate) amorphous polymers, and the advantages in their utilizaand dry Solvent were then added in measured amounts, ti t f these i d properties p l i and the resulting mixture was held at a given temperature tion methods for the production of crystallizable polyfor Varying PerictdS of time- The P y was Tficoveffid mers vary according to the monomeric material polymy treatment with an alwhol and it was Purified y i d d h catalysts used tend to he ifi f the maceration in alcohol acidified with hydrochloric acid particular monomeric material subjected to the process. and in aklohol The polymer was then driid and whighcd- A t lh bl l o h l h h can b It was tested for degree or" crystallizability by soaking in particular monomeric material subjected to the process. methyl isohhtyl ketohe alone in admixture with 1/5 talline poly(methyl methacrylate) can be produced by P of heptahe for twenty hours and delfifminhlg treatment with solvents which cause swelling of the amorintensity and yp of lf P h reduced phous lli m b/( h l h l If h specific viscosity at a concentratlon of 0.1% 111 ethylene degree of crystallinity in the polymer chains is sufficient- Chloride was also determinedly high, a crystalline polymer is separable and the poly- The data on specific examples are set forth in the table. mer which will yield this crystalline polymer is referred In 311 Cases the 3 Pattern Showed only one yp of t h i as a nj m pelymeh crystallinity for each of the different polymers in the Crystallizable poly(methyl haloacrylates), on the oth tabulated examples as well as in the numerous variations hand, have not been produced and crystalline poly(methyl 0f Gfighal'd h alld ketohe h p p hg the Catalyst haloacrylates) are unknown i h art, and in the wide variat on of reactlon conditions. In the In accordance with the present invention, it has now Various examples it Shown that high cohverslohs to been found that readily crystallizable poly(methyl methp y of g Viscosity e Possible with this catalyst acrylate) and readily crystallizable poly(methyl halo- The viscosity is expressed as RSV (reduced specific visacrylate) are produced by contacting methyl methacrylate cosity) which was determined on a 0.1% solution of the or methyl haloacrylate with a catalyst produced by reactpolymer dissolved in ethylene chloride at 25 C.

Table Example 1 2 3 4 5 6 7 s 9 10 11 12 13 14 15 16 17 Catalyst (Millimols) Benzalacetophenone 1 2 2 1 1. 5 2 2 1 1 1 1 2 1 1 3 O. 5 Dibenzalacetone 1 C2H5MgCl 1 1. e5 2 2 1 1 1 1 2 1 1 3.6 0.5 C2H MgB1'. (CHa)2CHMgOl Ool-l MgOl CHsMgI Solvents (Parts):

Heptane Toluene..-

Ether Monomer (Parts):

Methyl Methacrylate Methyl Ohloroacrylate Methyl Bromoaerylata Polymerization:

Temperature, C Time (hours) Conversion (percent) RSV ing a Grignard reagent, RMgX, in which X is a halogen and R is a hydrocarbon radical of 1 to 18 carbon atoms with a ketone of the formula The catalyst of this invention is the complex produced by the combination or reaction of a Grignard reagent of formula RMgX, wherein X is a halogen (chlorine, bromineor iodine) and R is a hydrocarbon radical, with a ketone of the formula wherein R, R" and R' are hydrogen or hydrocarbon radicals of 1 to 8 carbon atoms and R"" is a hydrocarbon radical of 1 to 18 carbon atoms. Examples of the hydrocarbon radicals are: methyl, ethyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, octyl, cyclopentyl, cyclohexyl, styryl, propenyl, octadecyl, benzyl, phenyl and tolyl. One of R and R" is preferably a hydrocarbon radical.

Specific examples of the Grignard reagents useful in this invention are: methyl magnesium iodide, ethyl magnesium chloride, isopropyl magnesium chloride, phenyl magnesium bromide, benzyl magnesium chloride, cyclohexyl magnesium chloride, tolyl magnesium chloride, p-methyl phenyl magnesium chloride, propenyl magnesium chloride.

Specific examples of ketones from which the catalyst of this invention is produced are:

The reaction between the ketone and the Grignard reagent is eirected in the usual manner for effecting a reaction between such reagents using solvents and temperatures of reaction well known in the art. Thus dry solvents such as ether, pentane, dioxane, or benzene may be used and the ether in which the Grignard reagent is produced may be displaced partially or entirely by another solvent before reacting with the ketone. A satisfactory temperature range for producing the catalyst is 20 C.

to 150 C. but a much wider range may be used since the temperature is not critical. As is usual in Grignard reactions, Grignard reagent-reactive substances are avoided, and dry reagents and an inert atmosphere are a used. The catalyst is used in the form of the complex produced by combining the Grignard reagent and ketone without further chemical treatment! Its exact chemical structure is not known but it appears to be the addition product of one mole of Grignard reagent and one mole of ketone. If an excess of ketone is used, it does not act as an inert solvent, however, since it weakens the activity of the catalyst complex. It a small excess of Grignard reagent is used, the catalyst is a mixture of the catalyst of this invention and other complexes. .An excess of Grignard reagentin the catalyst mixture may be tolerated but is not. desired since more than about a 75% excess gives a crystallizable product which has a less definite complex is added for convenience in the solvent in which it is produced. However, the solvent may be distilled off if desired and the solid catalyst may be added to the liquid methyl methacrylate monomer. It is desirable to use a solvent in the polymerization process to aid in the production of a more uniform product. Solvents which may be used include the lower volatile ethers such as ethyl ether, diisopropyl ether and mixed others such as ethyl isopropyl ether; aliphatic hydrocarbons such as ethane, propane, butane, pentanes, hexane, heptane and octanes; cyclic hydrocarbons such as cyclopen-tane, methyl cyclopentane, and cyclohexane; aromatic hydrocarbons such as benzene, toluene, and the xylenes; and mixtures.

When aromatic solvents are used, the polymer is usually in solution and may be recovered by diluting with an aliphatic hydrocarbon to effect its precipitation.

The amount of Grignard reagent-lcetone complex used as a catalyst may be selected from the range of 0.05 to 5 mol per mol of monomer to be polymerized. The larger amounts give more rapid polymerization than the smaller amounts and result in polymers of lower viscosity. In the preferred temperature range, the preferred amount of catalyst is 0.2 to about 2.0 mol.

The temperature influences the rate of polymerization and the molecular weight of the polymer, high temperatures in the range of 100 C. giving a lower viscosity polymer than lower temperatures. The temperature may be in the range of 60 C. to about 100 C. for the production of crystalline solid polymers, but a temperature in the range of about 0' C. to about 50 C. is preferred. At temperatures above about 100 C. low molecular weight polymers are produced, and the amount of crystalline polymer is thus too low to separate from the resinous polymer in the mixture. The most practical temperature range is 0 C. to about 30 C. Temperatures below about 0 C. require a longer polymerization time.

The polymer produced in the process of this invention is freed of the catalyst complex by steeping in alcohol preferably with maceration followed by contacting with alcoholic hydrochloric acid and finally washing with water. The product is generally dried by washing with alcohol to remove occluded water and then evaporating the alcohol. Many variations of this general procedure are obvious to one skilled in purification of polymeric materials. The polymer as so treated when produced by this process is either crystalline without further treatment or becomes crystalline if allowed to steep in a methyl isobutyl ble polymers produced by the process of this invention are readily identified by Xray diffraction spectra. The following X-ray diffraction data serve for identification of these crystalline polymers.

Poly(Methyl Poly(Methy1 P0ly(Metl1yl Iethacrylate) Ohloroacrylate) Bromoacrylate) Line (A.) Relative 1 Line (A.) Relative Line (A.) Relative 1 intensity intensity intensity 10. 8 9.2 10 8. 0.5 6. 10 7.6 8 7. l0 5. 5 6.0 6 4. 2 4. 2 '5. 8 4. 2 3. 3 4. 2 1 4. 1 2. 0.5 3. 2 l 3. l 2. 2 3. 2 2 3. 2 2. i 3 1 3. 1

1 10=strongest intensity, O=l ackgr0und density of exposed film. 2 Broad.

These values are found to be fairly uniform regardless of the difference in molecular weight of various samples within the limits of experimental error which may be as high as 5%.

The catalyst of this invention has two unique properties requisite for the production of a crystallizable polymer in high yield. First, it has the property of directing the orientation of the polymer toward a uniformity of configuration along the chain so that a single type of crystalline pattern is attained. Secondly, it has a degree of activity for producing a polymer of high molecular weight at ordinary temperatures. This is particularly observable in the case of methyl methacrylate. Without these properties, the polymer formed would not be readily crystallizable or be obtained in high yield as a polymer of high viscosity.

The crystallizable polymers produced in accordance with this invention can be used in the preparation of fibers, films, coatings and molded articles of improved properties. The higher melting point of fibers and films of the crystallized polymers is particularly advantageous. The crystallized polymer coatings additionally have greater cohesive properties than non-crystalline polymers and also diffuse sunlight so that there is greater resistance to outdoor Weathering. The crystallinity in lacquers may be developed by solvent swelling or on aging in normal usage and exposure to the heat of the sun.

What I claim and desire to protect by Letters Patent is:

1. The method of preparing a readily crystallizable polymer which comprises contacting a monomer of the group consisting of methyl methacrylate and methyl haloacrylate at a temperature in the range of about 60 to about 100 C. in an inert atmosphere with from about 0.5 to about 50 millimoles per mole of said monomer of a Grignard reagent-ketone catlyst complex produced by mixing a Grignard reagent, RMgX, in which X is a halogen and R is a hydrocarbon radical of 1 to 18 carbon atoms with a ketone of the formula RI! R!!! in which R, R" and R are selected from the group consisting of hydrogen and hydrocarbon radicals of 1 to 8 carbon atoms, and R" is a hydrocarbon radical of 1 to 18 carbon atoms, in a molar ratio of Grignard reagent to ketone of from about 1:1 to about 1.75: 1.

2. The method of claim 1 in which the ketone of the catalyst complex is benzalacetophenone.

3. The method of claim 1 in which the ketone of the catalyst complex is dibenzalacetone.

4. The method of preparing a readily crystallizable polymer which comprises contacting a monomer of the group consisting of methyl methacrylate and methyl haloacrylate at a temperature in the range of about -60 to about 100 C. in an inert atmosphere with from about 0.5 to about 50 millimoles per mole of said monomer of a catalyst complex formed by the combination of ethyl magnesium chloride with benzalacetophenone, in a molar ratio of from about 1:1 to about 1.75 1.

5. The method of preparing a readily crystallizable polymer which comprises contacting a monomer of the group consisting of methyl methacrylate and methyl haloacrylate at a temperature in the range of about to about C. in an inert atmosphere with from about 0.5 to about 50 millimoles per mole of said monomer of a catalyst complex formed by the combination of ethyl magnesium chloride and dibenzalacetone, in a molar ratio of from about 1:1 to about 1.75:1.

6. The method of preparing a readily crystallizable poly(methyl methacrylate) which comprises contacting methyl methacrylate at a temperature in the range of about 60 to about 100 C. in an inert atmosphere with from about 0.5 to about 50 millimoles per mole of methyl methacrylate of a catalyst complex formed by the combination of phenyl magnesium chloride with benzalacetophenone, in a molar ratio of from about 1:1 to about 1.75 :1.

7. The method of preparing a readily crystallizable poly(methyl methacrylate) which comprises contacting methyl methacrylate at a temperature in the range of about -60 to about 100 C. in an inert atmosphere with from about 0.5 to about 50 millimoles per mole of methyl methacrylate of a catalyst complex formed by the combination of isopropyl magnesium chloride with benzalacetophenone, in a molor ratio of from about 1:1 to about 1.75:1.

8. The method of preparing a readily crystallizable poly(methy1 methacrylate) which comprises contacting methyl methacrylate at a temperature in the range of about -60 to about 100 C. in an inert atmosphere with from about 0.5 to about 50 millimoles per mole of methyl methacrylate of a catalyst complex formed by the combination of methyl magnesium iodide with benzalacetophenone, in a molar ratio of from about 1:1 to about 1.75 :1.

9. The method of preparing a readily crystallizable polymer which comprises contacting a methyl haloacrylate at a temperature in the range of about -60 to about 100 C. in an inert atmosphere with from about 0.5 to about 50 millimoles per mole of methyl .haloacrylate of a catalyst complex formed by the combination of ethyl magnesium chloride and benzalacetophenone, in a molar ratio of from about 1:1 to about 1.75:1.

Schildknecht: Polymer Processes (1956), Interscience Publishers, Inc., New York, page 221 relied on.

Chem. Abstracts, Volume 33, page 9282 (1939); Volume 30, page 1783, (1936); and vol. 44, page 8857 (1950).

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,,151 102 September 29, 1964 Abraham Kutner "particular monomeric and insert instead duced v and the crys Signed and sealed this 9th (jay of February 1965.

(SEAL) Attest:

Commissioner of Patents 

1. THE METHOD OF PREPARING A READILY CRYSTALLIZABLE POLYMER WHICH COMPRISES CONTACTING A MONOMER OF THE GROUP CONSISTING OF METHYL METHACRYLATE AND METHYL HALOACRYLATE AT A TEMPERATURE IN THE RANGE OF ABOUT -60* TO ABOUT 100*C. IN AN INERT ATMOSPHERE WITH FROM ABOUT 0.5 TO ABOUT 50 MILLIMOLES PER MOLE OF SAID MONOMER OF A GRIGNARD REAGENT-KETONE CATLYST COMPLEX PRODUCED BY MIXING A GRIGNARD REAGENT, RMGX, IN WHICH X IS A HALOGEN AND R IS A HYDROCARBON RADICAL OF 1 TO 18 CARBON ATOMS WITH A KETONE OF THE FORMULA 